How can I make a good looking candle flame effect to be used in Unreal Engine 4
As it seems to be an asset with little significance for details, I'd suggest using a textured plane set as billboard (i.e. always facing the camera).
You can either draw the texture with a few frames of animation or animate the top vertices of the plane, so you get a little bit of flicker. Don't forget to use transparency with your texture.

Obviously, the texture should be set for "emission".